The camps that were officially and only designed for killing occured right after the Wannsee Conference on January 20, 1942 in Poland.
These included the six infamous camps:
Chelmno, Belzec, Sobibor, Treblinka, Auschwitz-Birkenau, and Majdanek.
However, the nearly hundred or more other detention and slave labor camps in other areas occupied by Nazi Germany starting with Dachau in 1933 had horrible conditions any many times served effectively as killing camps.
For example, just to name two camps that were not set up as killing camps, but ended up killing thousands and thousands were:
Bergen Belsen -- 50,000 killed
Theresienstadt -- 33,000 killed
It's very important to remember also that the Nazis didn't just kill in concentration camps.
They also killed in prisoner of war camps. For example they killed 3.5 Soviet prisoners of war.
It is estimated Nazis killed about one million Jews and others by hanging or shooting within several weeks of invading the Soviet Union.
Lastly, Nazis even planned to kill entire cities by starvation. Consider the 872 day seige of Leningrad where the Nazis killed about another million.
1940.
1939
Auschwitz was established by Heinrich Himmler.
Auschwitz was created on the orders of Himmler and established by the work of Hoess.
Auschwitz I opened on May 1941 Auschwitz II Birkenau opened on October 1941 Auschwitz III Monowitz opened on October 1943
Auschwitz is infamous for being the location of a group of concentration camps established by the Nazis, used for the forced labor and systematic murder of human beings in World War 2.
It started in May 1940.
Auschwitz Birkenau was established at Auschwitz but Auschwitz is now called Oświęcim.
Auschwitz was established by Heinrich Himmler.
Hoess
Auschwitz concentration camp was first established on March 22, 1933
Auschwitz was created on the orders of Himmler and established by the work of Hoess.
Auschwitz was established as a concentration camp in June 1940 and later expanded.
October 1941
Auschwitz was established in May 1940. It's purpose was to carry out Hitler's Final Solution to the Jewish problem; to kill Europe's Jews.
The summer of 1940.
Auschwitz I opened on May 1941 Auschwitz II Birkenau opened on October 1941 Auschwitz III Monowitz opened on October 1943
1945
Auschwitz is infamous for being the location of a group of concentration camps established by the Nazis, used for the forced labor and systematic murder of human beings in World War 2.